I agree with verdant there is a change in bass and detail in my system and very noticeable. I have a Bruce Moore Preamp that recommends reverse polarity which I do. I have a invert phase switch on phono pre with a remote so I can switch from my chair. So I can A/B fast. I find I use the switch a lot it's crazy because I have it switched at the speaker. Different songs sound better on the same album with the switch on and off, so for me there is no right answer whether to use it or not. I do find I use the switch off with polarity reversed 2/3 of the time maybe.
Impact of phase inversion by preamp
This will be my first post on this forum so I thought I’d pose a question I’ve always wondered about. I have a Conrad Johnson Premier 18LS preamp that I’ve been extremely happy with since first acquiring it some years ago. This is a solid state single ended, single stage design that inverts the phase of the input signal at the output. The manual states that you should reverse the connections to the speakers to account for this. Obviously this is easily done but I really can’t see how it would really matter as long as things are connected consistently between the left and right channels. I’d be interested to hear what others have to say on this subject.